Determination of Sulphonylurea Glimepiride in Dog Serum by RP-HPLC with Pre-column Derivatization

Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.

Determination of Sparfloxacin in Human Urine by Reversed-Phase High Performance Liquid Chromatography With Nitrous Acid and Hydroiodic Pre-Column Derivatization

Sparfloxacin can be oxidized by nitrous acid, then react with hydroiodic acid to form a fluorescent derivative. Based on this, a reversed-phase high performance liquid chromatographic pre-column derivatization new method is described for the determination of sparfloxacin in human urine. The linear range is 0.05 mg/L to 4.0 mg/L, the recoveries are 91.5%similar to 95.7% and the RSD is 1.2%similar to4.2%. The results showed that this method is suitable for the determination of sparfloxacin in human urine.

Determination of 18 Kinds of Amino Acids in Fresh Tea Leaves by HPLC Coupled with Pre-column Derivatization

A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.

High－Performance Liquid Chromatographic Determination Of N－Nitrosoamines by Pre－Column Fluorescence Derivatization with 9－Phenanthrene Chloride

A sensitive high-performance chromatographic method for the detection of N-nitrosoamines with pre-column fluorescence derivatization has been developed.Eight representative N-nitrosoamines, which were separated on a reversed-phase C18column with methanol - Water-triethylamine as eluent, were used as model compounds to optimize the derivathation and the chromatographic conditions. The relative standard deviations(n=7) at an analytical concentration of 4×10-6 mol/L are less than 5%. The detection limits (signal-to-noise ratio=3) for the N-nitrosoamines compounds are in the range of 0.02～0. 14 nmol per injection volume(10μl).

Enantioresolution of a Series of Chiral Benzyl Alcohols by HPLC on a Dinitrobenzoylphenylglycine Stationary Phase after Achiral Pre-Column Derivatization

High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral derivatization was developed. Cheap and easy available aromatic acid chlorides were used as derivatization agents. Good to excellent separations of the enantiomers were achieved in all cases in relatively short analytical runs. It was shown that the enantiorecognition depends on the substituents both in the starting alcohol and in the acid chloride. The method presents an efficient alternative to the direct analyses on polysaccharide and cyclodextrine-derived stationary phases.

Experimental study on seismic behavior of circular RC columns strengthened with pre-stressed FRP strips

Bonding fiber reinforced polymer （FRP） has been commonly used to improve the seismic behavior of circular reinforced concrete （RC） columns in engineering practice. However, FRP jackets have a significant stress hysteresis effect in this strengthening method, and pre-tensioning the FRP can overcome this problem. This paper presents test results of 25 circular RC columns strengthened with pre-stressed FRP strips under low cyclic loading. The pre-stressing of the FRP strips, types of FRP strips and longitudinal reinforcement, axial load ratio, pre-damage degree and surface treatments of the specimens are considered as the primary factors in the tests. According to the failure modes and hysteresis curves of the specimens, these factors are analyzed to investigate their effect on bearing capacity, ductility, hysteretic behavior, energy dissipation capacity and other important seismic behaviors. The results show that the initial lateral confined stress provided by pre-stressed FRP strips can effectively inhibit the emergence and development of diagonal shear cracks, and change the failure modes of specimens from brittle shear failure to bending or bending-shear failure with better ductility. As a result, the bearing capacity, ductility, energy dissipation capacity and deformation capacity of the strengthened specimens are all significantly improved.

Coupling of on-Line Pre-Column Oxidative Cleavage and Solid-Phase Enrichment with Liquid Chromatography Using an Eco-Friendly Analytical Procedure to Determine Low Levels of Methotrexate

A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 mm i.d.) for enrichment and separation was developed and validated to determine low levels of methotrexate (MTX). The method was based on oxidative cleavage of MTX into highly fluorescence products, 2,4-diaminopteridine-6-carboxaldehyde and the corresponding 2,4-diaminopteridine-6-carboxylic acid, during the flow of phosphate buffer (0.04 M, pH 3.4) containing the analyte through the packed reactor of cerium (IV) trihydroxyhydroperoxide (CTH) at a flow-rate of 0.2 mL/min and 40℃. The fluorescent products were enriched on the head of ODS analytical column for the final separation. The separation was performed at room temperature using an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 10:90 (v/v). The eluent was monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method was successfully applied, without any interference from the excipients, for the determination of drug in tablets and vials with a detection limit of 0.06 ng/mL from 500 ?L of sample MTX.

柱前衍生-高效液相色谱法测定巴戟天中氨基酸含量及营养价值评价

建立柱前衍生-高效液相色谱法测定巴戟天中氨基酸含量,采用氨基酸比值系数法评价其营养价值。采用盐酸水解法制得巴戟天氨基酸供试品溶液,以异硫氰酸苯酯和三乙胺为柱前衍生化试剂,采用高效液相色谱法,使用Ultimate Amino Acid色谱柱(4.6 mm×250 mm,5μm)以0.1 mol/L无水乙酸钠-乙腈为流动相,梯度洗脱,柱温40℃,检测波长为254 nm,测定氨基酸含量;通过氨基酸比值、氨基酸比值系数、氨基酸比值系数分等评价其营养价值,并采用系统聚类和主成分分析对其进行分类分析。结果表明,15种氨基酸线性关系良好,相关系数r≥0.9996。16份巴戟天氨基酸总含量为17.87~102.15 mg/g,均检测到15种氨基酸,其中包含6种必需氨基酸,占总氨基酸含量的14.15%~32.06%;8种药用氨基酸,占总氨基酸含量的45.20%~56.31%。限制氨基酸为苏氨酸和亮氨酸,氨基酸比值系数分为33.87~61.31。不同巴戟天样品氨基酸组成相关性显著;主成分分析提取2个主成分,累计方差贡献率为97.085%,可将16批巴戟天分为三类。该实验测定方法简单有效,可同时分离测定15种氨基酸,精密度与重复性良好,有较高的药用价值,可为巴戟天的品质分析和资源开发利用提供参考。

AQC柱前衍生高效液相色谱方法测定康复新液中游离氨基酸和总肽的含量

目的应用6-氨基喹啉基-N-羟基琥珀酰亚氨基氨基甲酸酯(AQC)柱前衍生化技术,建立康复新液中游离氨基酸和总肽的高效液相色谱(HPLC)含量测定方法,并以总肽含量为指标对市售样品进行检测。方法以十八烷基硅烷键合硅胶为填充剂(Kromasil 100-5 C18色谱柱);60%乙腈(A)-0.14 mol·L^(-1)三水合乙酸钠溶液,用磷酸调节pH值至5.0(B)为流动相,梯度洗脱;柱温:39℃;流速:1.0 mL·min^(-1),检测波长:248 nm。结果14种氨基酸均能达到良好的分离效果;门冬氨酸、谷氨酸、丝氨酸、组氨酸、甘氨酸、精氨酸、苏氨酸、丙氨酸、脯氨酸、缬氨酸、赖氨酸、异亮氨酸、亮氨酸和苯丙氨酸分别在2.0~99.7、3.4~168.5、2.8~139.6、4.0~201.4、4.8~238.1、6.7~336.9、3.3~167.5、9.7~487.3、4.1~202.5、4.4~221.6、5.4~270.5、3.3~166.8、4.8~240.8、4.7~236.6μg·mL^(-1)范围内呈现良好的线性关系(r=0.9995~1.0000);游离氨基酸的平均加样回收率(n=6)为86.8%~108.1%,RSD为2.8%~4.4%,总肽酸水解氨基酸的平均加样回收率(n=6)为83.2%~102.7%,RSD为0.1%~3.1%;仪器精密度、重复性、稳定性实验的RSD均小于5.0%。结论该方法与现行质量标准的紫外分光光度法比较,二者测定的总氨基酸含量结果基本一致,但前者的专属性、重现性更优;以具有生物活性的总肽为质控指标,针对性更强,可为康复新液的质量评价提供更科学、合理的方法。

柱前衍生高效液相荧光检测法测定复方氨基酸注射液中甲硫氨酸亚砜的含量

目的建立测定复方氨基酸注射液中甲硫氨酸亚砜质量分数的高效液相色谱法。方法采用柱前衍生HPLCFLD法,色谱柱为Agilent Poroshell 120 EC-C18柱(3.0 mm×100 mm,2.7μm)或效能相当的色谱柱,以乙酸钠四氢呋喃溶液为流动相A,乙酸钠溶液-乙腈-甲醇(体积比20∶40∶40)为流动相B,流速为1.0 mL/min,采用荧光检测器,激发波长为233 nm,发射波长为441 nm。结果甲硫氨酸亚砜质量浓度在0.02605~2.605μg/mL范围内线性关系良好(r=0.9996),检测限为1.3×10^(-3)ng,平均回收率为100.1%,RSD为0.3%。结论建立的方法操作简单、准确、灵敏度高,适用于复方氨基酸注射液中甲硫氨酸亚砜的测定。

市售酱油产品生物胺含量的检测与食用安全性分析

为了揭示酱油中生物胺存在种类和水平,该研究采用丹磺酰氯柱前衍生结合高效液相色谱法对我国市售的9个品牌57种(生抽41种和老抽16种)酱油中的生物胺含量进行了分析。结果表明,酱油中苯乙胺、腐胺、组胺、酪胺是我国市售酱油中的主要生物胺成分。生抽酱油中的总胺大部分在127.86~1273.40 mg/L,其中组胺和酪胺的含量范围分别在10.82~368.91 mg/L和0~582.77 mg/L之间。老抽酱油中总生物胺的含量分布范围为200.54~904.61 mg/L,组胺与酪胺的含量范围分别为35.07~302.35 mg/L和38.75~479.61 mg/L。风险评估分析结果表明,生抽和老抽酱油中组胺和酪胺的急性风险指数H分别为7.69%、1.99%和2.10%、0.55%,均远低于100%,且两者的慢性风险指数E值较小,范围在0.15%~1.65%之间。另外,生抽和老抽的食品安全指数(IFS)在0.001~0.016之间,远低于1。该研究表明由食用酱油中引入的组胺和酪胺对人体健康无明显的负面危害,我国市售酱油食用安全性相对较高。

OPA柱前衍生化HPLC同时测定川红工夫红茶20种氨基酸含量

建立在线柱前衍生液相色谱法同时测定不同品种川红工夫红茶中的20种氨基酸含量,并评价其与滋味品质相关性。以邻苯二甲醛(OPA)为衍生试剂,利用液相色谱仪的自动进样器进行柱前衍生,采用Hypersil BDS C 18柱(150 mm×4.6 mm,3μm),以0.016 mol/L的磷酸盐缓冲液(pH=8.2)与甲醇-乙腈-水(4.5∶4.5∶1,V∶V∶V)组成流动相进行梯度洗脱,流速为1.0 mL/min,柱温50℃,荧光检测器激发波长340 nm、发射波长450 nm;通过相关分析,比较不同滋味属性氨基酸含量与红茶滋味的相关性。结果表明:20种氨基酸在0.195~2.584μg/mL的范围内与各自峰面积呈良好的线性关系,其相关系数为0.9954~0.9999,检测限为0.006~0.036μg/mL,定量限为0.020~0.184μg/mL,加标回收率为90.40%~99.13%;除四川群体种红茶和梅占红茶中未检出组氨酸外,其余氨基酸均在5个品种红茶中检出,氨基酸总量27.33~65.29 mg/g之间,其中含量最高的是黄金芽红茶,氨基酸组分中,含量最高的是茶氨酸,然后是天冬氨酸和谷氨酸;红茶中的鲜味氨基酸、甜味氨基酸、苦味氨基酸、氨基酸总量与红茶的鲜味、甜味和综合滋味评分呈显著或极显著正相关,对红茶滋味的鲜爽度和浓强度起着重要作用。采用OPA柱前衍生反相液相色谱荧光法检测氨基酸组分精密度和回收率高,具有成本低、快速、准确的特点,可用于红茶中20种氨基酸组分的快速测定。

柱前衍生-高效液相色谱法测定化妆品中16种氨基酸的含量

提出了2,4-二硝基氟苯(DNFB)柱前衍生-高效液相色谱法测定化妆品中甘氨酸、亮氨酸、组氨酸、缬氨酸、甲硫氨酸、脯氨酸、半胱氨酸、苏氨酸、谷氨酸、赖氨酸、酪氨酸、精氨酸、异亮氨酸、色氨酸、苯丙氨酸、丙氨酸等16种氨基酸含量的方法。取化妆品样品5 g置于50 mL离心管中,加入5 mL水,超声10 min,加热煮沸15 min,冷却后加入15 mL 35 g·L^(−1)磺基水杨酸溶液,以转速10500 r·min^(−1)离心20 min。取全部上清液,用35 g·L^(−1)磺基水杨酸溶液定容至25 mL。取1 mL样品溶液,加入0.5 mol·L^(−1)碳酸氢钠溶液(pH 9.0)1 mL和1%(体积分数)DNFB衍生溶液1 mL,混匀,于60℃加热10 min,冷却后用0.01 mol·L^(−1)磷酸二氢钾溶液(pH 7.0)定容至5 mL,所得溶液中16种氨基酸经X Bridge C_(18)色谱柱分离,以不同体积比的含1%(体积分数)N,N-二甲基甲酰胺的0.05 mol·L^(−1)乙酸钠缓冲液(pH 6.5)-体积比1∶1的乙腈-水混合溶液为流动相进行梯度洗脱,在360 nm处检测。结果表明:16种氨基酸标准曲线的线性范围均为0.004~40.0 mg·L^(−1),检出限(3S/N)为0.1~0.2 mg·kg^(−1);对空白样品进行3个浓度水平的加标回收试验,回收率为89.0%~105%,测定值的相对标准偏差(n=7)均不大于10%。方法用于11种市售化妆品分析,检出的氨基酸成分多为组氨酸、甘氨酸、甲硫氨酸、谷氨酸。

不同采收期枇杷叶中氨基酸的组成与分析

目的 对12个月份采收期枇杷叶的氨基酸成分组成及含量变化进行分析,为确定枇杷叶采收期及资源利用提供理论依据。方法 采用异硫氰酸苯酯柱前衍生化高效液相色谱法测定不同月份枇杷叶氨基酸组成及含量;采用SPSS22.0版软件进行数据统计学差异及相关性分析;根据世界卫生组织(WHO)和联合国粮农组织(FAO)提出的理想模式及朱圣陶提出的氨基酸比值系数法,对不同采收期的枇杷叶氨基酸进行评分。结果 不同采收期枇杷叶中均含有17种氨基酸,7种人体必需氨基酸(EAA)、9种儿童必需氨基酸(CEAA)及9种药用氨基酸。17种氨基酸分别是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、组氨酸、精氨酸、苏氨酸、丙氨酸、脯氨酸、酪氨酸、缬氨酸、甲硫氨酸、胱氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸,它们的平均含量分别为3.41~7.23、4.64~9.66、2.05~3.75、2.99~4.95、0.01~1.56、2.33~4.85、2.10~4.03、2.67~5.48、5.37~7.64、1.45~3.49、2.70~5.53、0.01~0.48、3.64~4.78、1.91~4.15、3.96~7.83、2.39~4.60、1.85~3.65 mg·g^(-1)。不同采收期枇杷叶中17种氨基酸、总氨基酸(TFAA)、EAA总量、CEAA总量、药用氨基酸、苦味氨基酸的含量间差异有统计学意义(P<0.05);苦味氨基酸在总氨基酸中的百分含量较稳定。不同采收期枇杷叶的EAA含量为44.26%~50.33%,明显高于WHO/FAO模式值(35.00%);EAA/非必需氨基酸(NEAA)均值(55.67%)和EAA/TFAA均值(35.74%)分别接近WHO/FAO模式值的60%、40%;不同采收期枇杷叶的17种氨基酸含量峰值前2位是7月和11月;氨基酸比值系数分(SRC)值为62.53~76.17,前3位为11月、8月及7月。赖氨酸为枇杷叶的第一限制氨基酸。苦味氨基酸与药用氨基酸、TFAA呈正相关(P<0.01)。结论 枇杷叶中氨基酸种类齐全,组成合理,具有较佳开发利用价值;不同月份氨基酸的含量差异大,7月和11月是枇杷叶氨基酸合理开发利用的较佳时期。

柱前衍生气相色谱法测定沙棘中脂肪酸的含量

本研究旨在建立柱前衍生-气相色谱法测定沙棘中脂肪酸的含量。采用索氏提取法提取沙棘中的脂肪油,甲酯化后,采用气相色谱法测定沙棘中脂肪酸成分。结果表明,柱前衍生测定的肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、α-亚麻酸线性范围良好,r均大于0.999 8;平均回收率均大于93.1%,RSD均小于2.8%;通过Spass软件分析沙棘果不同部位的种子、果皮、果肉分别被聚为一类表明3种药用部位的脂肪酸类成分可以分别作为鉴别沙棘不同部位的重要指标成分。其中种子中的亚油酸含量约为果肉、果皮的2倍,α-亚麻酸含量种子中高于果肉、果皮15倍以上通过棕榈酸与棕榈油酸的比值判断,随着贮藏时间的增长棕榈酸与棕榈油酸的比值越大;沙棘果在通过蒸制20min后干燥处理,脂肪酸类成分含量最佳。通过柱前衍生-气相色谱法测定沙棘中脂肪酸的含量,可用于沙棘的质量评价。

不同产地及加热方式文冠果仁中的氨基酸成分分析

目的 分析不同产地的文冠果仁氨基酸成分及加热方式对氨基酸的影响。方法 采用ZORBAX Eclipse Plus C18柱(4.6 mm×250 mm,5μm),样品以异硫氰酸苯酯进行柱前衍生化,以乙腈-甲醇-水(3∶1∶1)为流动相A,0.1 mol·L^(-1)的醋酸钠溶液(p H 6.5)-乙腈(93∶7)为流动相B,柱温35℃,检测波长254 nm。结果 17种氨基酸在1.806~225.200μg·m L^(-1)与峰面积呈良好的线性关系,各产地必需氨基酸、药用氨基酸、苦味氨基酸和儿童必需氨基酸占总氨基酸的含量分别为14.40%~18.99%、64.06%~73.79%、14.82%~17.09%、23.53%~29.30%,北方地区的文冠果仁氨基酸含量、必需氨基酸含量和药用氨基酸含量均比较高,文冠果仁经过加热处理后各类氨基酸均有所提高。结论 不同产地文冠果仁的氨基酸在含量和营养价值上具有差异,北方地区的文冠果仁氨基酸营养和药用价值较高,文冠果仁经过一定的加热后食用营养价值和药用价值得到提高。

两矿法氧化难处理金矿中的黄铁矿

对黄铁矿-软锰矿两矿法酸性浸出工艺进行了研究,考察了硫酸浓度、配矿比、反应时间、液固比、反应温度等因素对浸出率的影响,确定了单矿物最适宜的浸出条件,并在此基础上开展了甘肃某地难处理金矿的浮选金精矿预氧化-氰化浸出试验研究。结果表明,当配矿质量比FeS_(2)∶MnO_(2)=1∶6,反应温度90℃,液固比6∶1,初始硫酸浓度100 g/L,预氧化时间为12 h时,锰的浸出率达到76.0%。此时,黄铁矿的氧化率达到88.2%,预氧化渣氰化处理后金浸出率达到85.4%。

柱前衍生法-HPLC测定化妆品中甲醛的不确定度评定

分析柱前衍生法-HPLC测定化妆品中甲醛的不确定度。根据《化妆品安全技术规范》(2015年版)第四章理化检验4.12方法甲醛测定和JJF1059.1-2012《测量不确定度评定与表示》,建立分析柱前衍生法-高效液相色谱法测定甲醛的不确定度数学模型,通过对整个测定过程中的不确定度来源进行分析和合成,运用最小二乘法对甲醛标准曲线拟合不确定度进行评定。取样量为0.2 g时,置信区间为95%时,K=2,化妆品中甲醛含量为(14.9±0.072104)mg/g。

柱前衍生化液质联用法测定氯乙酰氯试剂中的乙酰氯和二氯乙酰氯

建立了柱前衍生化超高效液相色谱-三重四级杆联用(UPLC-MS/MS)法同时测定酰化试剂氯乙酰氯中的杂质乙酰氯和二氯乙酰氯的含量。以苯胺作衍生化试剂,采用Poroshell 120 Aq-C18(150 mm×2.1 mm, 2.7μm)为色谱柱,0.1%(V/V)甲酸水和乙腈为流动相,梯度洗脱,流速为0.3 mL/min。在电喷雾离子源(ESI),正离子监测下,采用多反应监测扫描(MRM)模式。乙酰氯和二氯乙酰氯分别在0.5~50 ng/mL和5~500 ng/mL范围内线性关系良好(R^(2)≥0.998 6),定量限为0.5和5 ng/mL,检出限为0.2和2 ng/mL;回收率(n=3)为90.8%~103.1%和92.5%~108.7%,RSD为1.4%~6.6%和0.9%~3.8%。衍生化产物室温放置24 h内稳定。方法准确可靠,简便高效,可用于氯乙酰氯中乙酰氯和二氯乙酰氯的同时检测。

云南金厂河铁矿石高效节能选矿工艺试验

云南金厂河铁矿为合理开发利用全铁品位30.47%的铁矿石,确定有效的选矿工艺流程,针对矿石中有用铁矿物嵌布粒度较细,且与脉石矿物紧密共生,导致矿石难以高效抛废的问题,在碎选工艺引入了高压辊磨超细碎选择性碎解技术,并与常规破碎(-10 mm)湿式磁选预选抛尾工艺进行了对比试验。试验结果表明:在磁性铁回收率相近的情况下,采用高压辊磨—湿式预选工艺抛出的尾矿量明显提高,高压辊磨湿式预选精矿分别采用两段阶段磨矿—单一磁选工艺和两段阶段磨矿—磁选—磁选柱分选工艺,最终获得的分选指标相近,基于降本增效及节能减排的目标,推荐高压辊磨—湿式磁选—两段阶段磨矿—磁选—磁选柱分选工艺,作为该铁矿石的原则选矿工艺流程。